Local anodization of permalloy film by atomic force microscope

Local anodization on a permalloy (Ni80Fe20) thin film by an atomic force microscope (AFM) in air was studied. Fabrication of uniform structure on the permalloy film was difficult in comparison with that on a Si(1 0 0) substrate. On the permalloy film, threshold voltage for the AFM anodization increased until 3 h after exposure to air. With passage of time, I-V curves on the permalloy film also changed from metallic behavior to insulating one. In addition, I-V curves varied at positions on the permalloy film. The oxide layer with time- and position-dependencies can induce non-uniform structure in AFM anodization. However, uniformity of structure was able to be improved by using method of fabrication of dots.